A track-type work vehicle such as a bulldozer has a track-type traveling unit. The track-type traveling unit includes a crawler belt apparatus, a sprocket wheel, an idler tumbler, roller devices, and the like. A crawler belt apparatus is generally configured by coupling a plurality of crawler belt links in an endless manner by means of pins and bushings, and attaching track shoe plates to the plurality of crawler belt links. The crawler belt apparatus is wound around the sprocket wheel, the idler tumbler, and the roller devices, and is configured to be rotationally drivable by engaging a sprocket tooth with a bushing and rotating the sprocket wheel.
The roller device has a shaft, a bushing, a roller shell, and the like. The shaft is fixed to the work vehicle. The roller shell is rotatably supported by the shaft through the bushing. The roller shell is worn by rolling on a rail surface of the crawler belt links during traveling. As the wearing of the roller shell proceeds, it would be necessary to replace the roller shell. For the replacement of the roller shell, a method of replacing a whole roller device may be taken, but such a method requires high cost. Therefore, there has been proposed a method of replacing only a roller shell rather than a whole roller device. The method of replacing only a roller shell rather than a whole roller device is disclosed in, for example, Japanese Patent Laying-Open No. 50-90026 (PTD 1).